The black sword that Tanjiro uses in the anime "Demon Slayer: Kimetsu no Yaiba" is called the "Nichirin Blade." The significance of the black color of the blade is that it symbolizes his determination to defeat demons and protect his loved ones. The black sword also represents Tanjiro's strength, resilience, and unwavering will to overcome challenges. Additionally, the black sword enhances the power of his breathing techniques, allowing him to effectively battle against demons.
